As one variable displacement exhaust turbocharger which is used for an exhaust turbocharger of an internal combustion engine and which is equipped with a variable nozzle mechanism for varying a vane angle of a plurality of nozzle vanes, the technique of JP 2010-19252 (Patent Document 1) is provided.
This technique of the related art is illustrated in the attached drawings. FIG. 6A is an illustration of a turbine housing 010. FIG. 6B is a partial enlarged view of section P of FIG. 6A. FIG. 6C is an exploded view of components of FIG. 6B.
A variable nozzle mechanism 0100 is configured such that a plurality of guide vanes (nozzle vanes) 080 is positioned between a lower vane ring 020 and an upper vane ring 030. The guide vane 080 is rotatably supported about an axis to control a flow rate of exhaust gas flowing in a turbine. The distance between the lower vane ring 020 and the upper vane ring 030 is maintained by a stepped spacer 050 which is positioned therebetween. The upper vane ring 030 and the lower vane ring 020 are attached to the turbine housing 010 by nuts 040 and metal fastening members 042.
Further, the stepped spacer 050 has a through-hole formed in the center so that the fastening member 042 can pass through the stepped spacer 050.
Meanwhile, another technique is disclosed in JP 4545068B (Patent Document 2). A variable displacement exhaust turbocharger of JP 4545068B is configured, as illustrated in FIG. 7, such that a drive ring 064 is arranged on a peripheral circumferential surface of a guide part 057 of a nozzle mount 055 to be disposed between a side face of a lever plate (not shown, disposed on a left side of the drive ring 064) and a side face of the nozzle mount 055 so that they are next to each other in the axial direction and a stud with a flange (a nail pin) 066 is fixed to a side part of the nozzle mount 055 to be in contact with an outer surface 064a of the drive ring 064 so as to prevent the drive ring 064 from moving in the axial direction, i.e. coming off toward the lever plate side.
In FIG. 7, a nozzle vane 068 is provided between the nozzle mount 055 and an annular support plate 070.